A serious question on plagiarism and pornography

Hello Steemians...I am just a week old here and didn't know where or how to put this question properly so I'm doing it here.
I initially followed a guy who I thought was a great photographer. Then I realised he was posting internet photos from different sources without proper credits or misleading credits. That was ok with me, but then he started resteeming boldhardcore pornography which began appearing on my news feed. Now I certainly believe that Steem is only for serious bloggers who want to share their ideas with the world and not for cheapstakes who would use other's creativity for a quick buck or use explicit content to gain easy cash.
I flagged a few of his posts to gain attention of the admins here and then he started writing on my posts in a threatening tone.
I might be wrong here but I am really not sure about the ethical contents in Steemit. I could really use some help from senior users and admins to solve
this issue.